A concentrically expansible needle retractor for minimally invasive surgery, of one the present inventors, is described in PCT/IL2000/00387, filed Jul. 4, 2000, the full disclosures of which are incorporated herein by reference.
An improved radial expansible retractor for minimally invasive surgery, of the present inventors, is described in PCT/IL2006/001250, filed Oct. 30, 2006, which has significant improvements which can benefit patients, the full disclosures of which are incorporated herein by reference.
FIG. 1a of the prior art is a perspective view schematic illustration of the improved radial expansible retractor, which will be referred to in the present application as a prior art radial expansible retractor (PARER) 100.
The illustrations show PARER ribs 141 touching each other, forming a hollow cylinder.
The prior art radial expansible retractor 100 is equipped with a PARER adaptor 169 and with a mechanism for transmitting gentle rotational mechanical movement from a PARER rotating wheel 161 to a PARER grooved disc 152, (not shown in the present illustrations).
FIG. 1b of the prior art is a perspective view schematic illustration of a PARER cover 151, of the prior art radial expansible retractor, in whose center is a PARER cover central perforation 151a of a suitable diameter for inserting a tubule and performing the medical procedure.
FIG. 1c of the prior art is a perspective view schematic illustration of a PARER grooved disc 152, of the prior art radial expansible retractor, in whose center is a PARER grooved disc central perforation 152a, of a suitable diameter for inserting the tubule and performing the medical procedure, and PARER grooves 152b, in the present case eight, designated to grant continuous forced movement to rib carrier pins.
In the case of need to open a shape other than a circle, the PARER grooved disc 152 can be used with at least part of the grooves having a different curve, and ends at different distances from the center. This difference necessarily results in different movement of each of the ribs, forming a lateral section, which is not circular.
Namely, the desired opening shape to be achieved by means of prior art radial expansible retractor must be determined prior to commencement of the medical operation.
FIG. 1d of the prior art is a perspective view schematic illustration of a of PARER channeled disc 153, of the prior art radial expansible retractor 100, in whose center is a PARER channeled disc central perforation 153a, of a suitable diameter for inserting the tubule and performing the medical procedure, and PARER channels 153b, in the present case eight, designated to grant continuous forced movement to the rib carrier, (not shown in the present figure). The PARER channels 153b are completely straight, and are pointed in the directions of the radiuses from a joint center of the PARER channeled disc 153. Their dimensions conform to those of rib carrier, and they are designated to enable strictly radial movement of PARER rib carrier 144, (not shown in the present figure), with regard to the aforementioned center.
Combination of the PARER channeled disc 153 and the PARER cover disc 151 is done by means of geometrically conforming both to each other, together forming a casing suitable for carrying PARER grooved disc 152 and granting it smooth rotational movement.
FIG. 1e of the prior art is lateral section schematic illustrations of the prior art radial expansible retractor 100.
The figure clearly showing PARER rib carrier 144 disposed within PARER channel 153b of the PARER channeled disc 153, with a PARER rib carrier pin 145 disposed within PARER groove 152b of the PARER grooved disc 152. The PARER rib carrier 144 connects to PARER rib base 142, which is the integral base of PARER rib 141, by means of PARER rib carrier bolt 147.
FIG. 1f of the prior art is a perspective view schematic illustration of a PARER rib 141 of the prior art radial expansible retractor.
At one end of PARER rib 141, the PARER rib's base 142 is disposed, into which the PARER rib base hole 143 is perforated. PARER rib 141 is formed as an elongated rod whose cross section can have many various geometrical shapes, also including the shape of a section of the wall of a cylinder.
FIG. 1g of the prior art is a perspective view schematic illustration of a PARER rib carrier 144 of the prior art radial expansible retractor. Its shape conforms for connection to the PARER rib's base 142 and it includes PARER rib carrier hole 146, and PARER rib carrier pin 145.
As far as minimal invasive methods of treatment of spinal stenosis are concerned, they are commonly performed with the assistance of tubular retractors.
A tubular retractor for minimally invasive surgery, of Bartie et al., is described in U.S. Pat. No. 6,210,325, granted Apr. 3, 2001, the full disclosures of which are incorporated herein by reference.
Use of tubular retractors for the performance of treatment of spinal stenosis has some very grave drawbacks, also including:
Over traumatization (disruption of muscles and nerves roots) of soft tissues upon insertion of a retractor, in most cases hammering is required to insert the retractor between muscle fibrils, resulting in destruction and disruption of soft tissues. During postoperative recovery, this kind of iatrogenic damage can inflict pain more severe than that caused by the pathology itself.
The tubular retractor frequently causes postoperative hemorrhaging and compression of the spinal cord, with motor function deterioration of the patient's extremities.
Uncontrolled soft tissue retraction (without measurement of retracted tissue pressure (RTP) and retracted tissue oxygen saturation (RTOS)) causes ischemic muscular degeneration-IMD and development of extremely rough postoperative scar tissue, resulting in circular compression of nerve roots and thus severe postoperative pain.
Very fast insertion of such tubular retractors causes splitting of muscles from vertebral bones and hemorrhaging. Surgeons must be aware that even though the surgery is completed effectively in a narrow space, symptoms can occur immediately if even a small hematoma is generated in this space.
Appropriate surgical tools and manual skills are required since surgeons must work in a narrow space. Further, there may be confusion regarding anatomical structures in such a limited space. Another problem is the limitations of effective decompression due to limited and constant (unchangeable, non-adjustable) diameters of tubular retractors.
Due to differing curvatures of vertebral lamina, tubular retractors don't enable the surgeon to approach lateral parts of lamina, including vertebral facets, and vision may be obstructed or disrupted by the use of tools in a narrow space with limited light.
Non-simultaneous unidirectional retraction of muscles causes uneven distribution of pressure to the soft tissues. Uncontrolled soft tissue retraction (without measurement of retracted tissue pressure (RTP) and retracted tissue oxygen saturation (RTOS)) causes ischemic muscular degeneration (IMD), and development of extremely rough postoperative scar tissue, resulting in circular compression of nerve roots and thus severe postoperative pain.
There is thus a widely recognized need for, and it would be highly advantageous to have, a surgical retractor for performing minimally invasive surgery, that will not have the aforementioned drawbacks, that will also enable working with massive tissue pressures to the extent that body tissues can apply, that will enable creating openings of various section shapes which can be changed in the course of operation, and that will be equipped with ribs of various shapes and sizes, that can be easily replaced without use of additional tools.